1. Field of the Invention
The present invention relates to a switching power supply.
2. Description of the Related Art
In order to generate a voltage higher or lower than the input voltage, a switching power supply is employed. The switching power supply includes an output inductor, an output capacitor, a switching transistor, and a control circuit configured to control the on/off operation of the switching transistor.
In some cases, in order to improve the efficiency when the switching power supply load becomes light, the frequency at which the on/off state of the switching element is switched, i.e., the switching frequency, is reduced. Such an arrangement provides an advantage of reduced loss due to the on resistance of a switching element, reduced loss due to the charging/discharging current that flows to/from the gate capacitance of the switching element, and reduced loss due to an rectifier element.